Bought my truck in may of 15, 4x4 worked great. We live up north, got through all kinds of snow. Left in Jan 16 to go to Florida for a week, came back, and there was a clunking noise when I shifted into 4x4. The light is on, to this day, but it clunks when you switch to 4x4 high. Haven't tried 4lo, but a rebuilt tcase here is 1200 bucks. When I bought the truck at the dealer, they replaced the entire IWE system because they said it was bad, and I didn't pay for it so it's fine. The dealer and my mechanic both said it had something to do with the tcase, but I figured I'd ask before I spend 1200 bucks at my mechanic for something I might not need. Any suggestions?